Find the GitHub commits behind a Bugsnag release's new errors

**Objective:** For the Bugsnag project `{project-name}`, show which errors first appeared in release `{app-version}` and which GitHub commits shipped between the previous release and that one.

**Step 1: Bound the release in Bugsnag**

Call `bugsnag-get-release` with `project-name` set to `{project-name}` and `app-version` set to `{app-version}`. If more than one release stage matches, prefer production and say which stage you used. Then call `bugsnag-get-release` again with `project-name` and `release-date.to` set to the day of that release, and take the release immediately before it in the same release-stage-name as the previous release.

Record both releases' release-date and source-control-revision, and the target release's errors-introduced-count.

**Step 2: Find the new errors**

Call `bugsnag-get-error` with `project-name` set to `{project-name}` and `last-seen.from` set to the target release-date. Keep only errors whose first-seen-date is on or after the target release-date and before the next release if there is one. Show at most `{max-errors}` of them (default 20), ordered by events descending.

**Step 3: Find what shipped on GitHub**

Call `github-get-commit` with `commit-date.from` set to the previous release-date and `commit-date.to` set to the target release-date. If both releases carry a source-control-revision, use them to mark the boundary commits and drop anything outside them.

**Step 4: Report**

1. Release summary: version, stage, date, errors introduced, and the commit range (previous revision to this revision).
2. New errors: error-class, message, severity, events, first-seen-date, error-url.
3. Commits in the release: short sha, author-name, commit-date, first line of message.
4. Suspects: for each new error, name any commit whose message mentions the error-class, the context, or the file from the error's events. To see the file, call `bugsnag-get-event` with `error-id` and `max-records` 1. Mark each link as a lead, not a finding.

**Rules & Guidelines:**

* `bugsnag-get-release`, `bugsnag-get-error` and `bugsnag-get-event` are on the bugsnag server. `github-get-commit` is on the github server.
* This is read-only. Do not call `bugsnag-assign-error`, `bugsnag-update-error-severity`, `github-add-issue` or any other Action tool.

**Validation:**

* If there is no previous release, use the seven days before the target release-date as the commit window and say so.
* If errors-introduced-count is 0 and no errors pass the first-seen filter, report the release as clean and still list the commits.
* If the commit window returns more than 100 commits, report the count, list the 30 most recent, and say the range is too wide to attribute.